(a) Field of the Invention
The present invention relates to a display device and more particularly to a display device having improved strength.
(b) Description of the Related Art
Thanks to the recent drastic development of semiconductor technologies, liquid crystal display (LCD) devices have been decreased in size and weight and enhanced in performance, and demand for such display devices has increased explosively.
LCD devices employing an LCD panel have advantages such as small size, small weight, and low power consumption, and have become attractive as a substitute for cathode ray tubes (CRT). Now, such LCD devices are used in small-sized products, such as cellular phones and portable digital assistants (PDAs), and middle-sized or large-sized products, such as monitors and televisions, which all require a display device.
LCD devices change a specific molecular alignment of liquid crystal to different molecular alignments through the application of a voltage and convert a change in optical characteristics, such as birefringence, optical rotary power, dichroism, and optical scattering, of liquid crystal cells emitting light due to the change in molecular alignment into a visual change. That is, LCD devices are light receiving display devices which display data using modulation of light in the liquid crystal cells.
Recently, an organic light emitting display (OLED) device has been in the spotlight as a next-generation display device. An OLED device uses a self light-emitting phenomenon to display an image, wherein light is emitted by combining electrons and holes injected from a cathode and an anode in an organic substance. Since the OLED device is an active element that emits light voluntarily, it has high emission efficiency and low power consumption. Further, because the OLED device can be driven even with a voltage of 15V or less, it is suitable for a small-sized display device and is low in manufacturing cost.
Therefore, LCD devices or OLED devices are used for most small-sized display devices, e.g., for cellular phones and so on. Since most cellular phones are manufactured in a folder type for the purpose of a user's convenience, dual display devices having display devices fitted to the front and back surfaces of a folder unit of a cellular phone are widely used in folder-type cellular phones.
As a small-sized display device may be dropped on the ground during utilization of a cellular phone, and so on, the display device should have enough strength to prevent damage. However, for the purpose of portability, it is difficult to further provide the cellular phone with an element for enhancing the strength of the cellular phone. Therefore, studies for preventing damage of the display device due to external impacts by changing elements of the display device have been made.
Specifically, in the display devices, since a panel unit displaying an image is made of a glass material, the panel unit is protected from external impacts by a chassis and a mold frame having higher strength than that of the glass material. Since the chassis is usually made of stainless steel, it has a large influence on the mechanical strength of the display devices. Therefore, various methods have been developed for minimizing the deformation of the chassis to improve the strength of the display devices.